This application claims the benefit of Korean Application Nos. 98-48008, filed Nov. 10, 1998 and 99-4678, filed Feb. 10, 1999, in the Korean Patent Office, the disclosures of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to the field of optical recording media, and more particularly, to a disc having information on the sizes of allocated spare areas and the remaining amounts thereof, in which an appropriate amount of a primary spare area is allocated upon initialization, and a supplementary spare area is allocated if the primary spare area is insufficient while being used after completion of initialization, a method of allocating the spare areas, and a method of managing the defects of the primary and supplementary spare areas.
2. Description of the Related Art
In recording media such as general discs, a spare area is allocated once upon initialization and no supplementary spare area is allocated during use of the disc. However, in order to increase the efficiency of using a disc, an appropriate amount of spare area is allocated according to the state of the disc upon initialization, and a supplementary spare area is allocated when the spare area allocated upon initialization is insufficient while the disc is being used.
According to a digital versatile disc random access memory (DVD-RAM) standard (DVD Specifications for Rewritable Disc, Part 1 PHYSICAL SPECIFICATIONS) version 1.0, each zone has one spare area, so that 24 spare areas are allocated upon initialization since a disc has 24 zones.
In the related art, as shown in FIG. 1, a flag representing the state of the spare area allocated to each zone within a defect management area (DMA) is constituted of only one bit, which represents whether or not a corresponding spare area can be used, i.e., whether it is occupied. Accordingly, a full spare area flag has 24 bits of information representing whether or not 24 spare areas are occupied. Also, this full spare area flag is stored in relative byte positions (RBP) 8 to 15 of a secondary defect list (SDL) of the DMA. When a bit representing a corresponding group is xe2x80x9c1xe2x80x9d, this represents that no spare area remains within the corresponding group, and when the bit is xe2x80x9c0xe2x80x9d, this represents that a spare area remains within the corresponding group.
Information on a spare area, which is constituted of only one bit as described above, represents only whether the spare area is occupied. On the other hand, in discs in which a supplementary spare area can be allocated after initialization, it is preferable that the supplementary spare area is allocated on a disc when the spare area has some room in a state of being almost occupied rather than when the spare area is completely occupied. However, a problem occurs in that the state in which the spare area is almost occupied cannot be represented by only the one bit.
Also, in the allocation of spare areas according to the existing DVD-RAM standard version 1.0, a predetermined amount of spare area is allocated to each zone upon initialization, the size of which is predetermined to be sufficient to process all defects that can be managed by a defect management method that is applied to a corresponding disc.
Here, in order to manage defects on a general recordable/rewritable disc, a slipping replacement method of skipping defects without providing logical sector numbers to the defects, is not used for defects generated upon initialization of the disc, which are called xe2x80x9cprimary defects.xe2x80x9d It is prescribed in the existing DVD-RAM standard version 1.0 that the position of a defective sector replaced by slipping replacement must be recorded in a primary defect list (PDL) in a DMA on a disc. Also, linear replacement for replacing error correction code (ECC) blocks of an erroneous zone with normal blocks in a spare area, is used for defects generated during use of the disc, which are called xe2x80x9csecondary defects.xe2x80x9d It is prescribed in the existing DVD-RAM standard version 1.0 that the position of a defective block replaced by linear replacement must be recorded in an SDL in a DMA on a disc.
However, when an appropriate amount of spare area is allocated according to the state of a disc upon initialization, and a supplementary spare area is allocated as the state of the disc becomes bad during use of the disc (xe2x80x9cbadxe2x80x9d meaning that the more the disc is used, the more defects it has), a more effective spare area allocating method is required. It is prescribed in the existing standard that in a recording and/or reproducing apparatus of a disc, the size of a buffer for temporarily storing defect management information existing on a disc is 32 Kbytes. Accordingly, a restriction is generated in that the actual number of defects that can be managed becomes less than the number of defects that can be recorded in the DMA on the disc.
Here, the defect management information includes PDL and SDL, and the sum of the sizes of the PDL and SDL is about 60 Kbytes. Thus, in the DVD-RAM standard version 1.0, PDL ranges from sectors 1 to 15, and the remaining sectors are set to be used to process SDL entries, so that the number of PDL entries and SDL entries that can be processed is restricted in accordance with the size (32 Kbytes) of a buffer of a recording and/or reproducing apparatus.
To solve the above problems, an object of the present invention is to provide a recording medium having information associated with the size and the remaining amount of a spare area allocated upon initialization, and with the size and the remaining amount of a spare area allocated after initialization.
Another object of the present invention is to provide a method of simply calculating and allocating a spare area for slipping replacement and a spare area for linearly replacing some defects, while a disc is being initialized, and a spare area for linear replacement which is required during use of the disc.
Still another object of the present invention is to provide a method of managing defects in a supplementary spare area which is allocated for linear replacement while the disc is being used.
Additional objects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
To achieve the first and other objects, the present invention provides a recording medium such that a primary spare area is allocated upon initialization and a supplementary spare area is allocated after initialization, and the sizes of the spare areas are determined by the number of defects generated upon initialization.
To achieve the second and other objects, the present invention provides a method of allocating a total spare area to manage defects in a disc recording and/or reproducing apparatus, the method including determining the minimum size of the total spare area using the number of primary defects generated during initialization; determining the maximum size of the total spare area that must be allocated according to the size of a memory device for defect management of the disc recording and/or reproducing apparatus; and allocating a primary spare area for slipping replacement and linear replacement using the minimum and maximum sizes of the total spare area.
To achieve the third and other objects, the present invention provides a defect management method for a disc recording and/or reproducing apparatus having a primary spare area allocated to replace primary defects generated during initialization using slipping replacement, and a supplementary spare area allocated to replace secondary defects generated after initialization using linear replacement, the method comprising allocating the supplementary spare area using an area that has already been linearly replaced, wherein defective blocks within the supplementary spare area which has already been linearly replaced are not used for linear replacement, and SDL entries within a defect management area with respect to the defective blocks are not changed.